The local scout group where after some oscillators for use in various games. I found a circuit diagram on the internet - see below.
I set about building two. They were both initally built on Veroboard and came together as:
And when split up looked like:
When boxed each had a volume and tone control on one end and two banana binding posts at the other. Power was supplied by a PP3 battery in a sliding battery draw so there was no reason to open the cases.
Below is an image of the finished pair.